The referendum, which must take place on 5 May 2011, will ask voters: "Do you want the United Kingdom to adopt the 'alternative vote' system instead of the current 'first past the post' system for electing Members of Parliament to the House of Commons?"

Predictably, a Bill that is allegedly about fairness in the voting system has already run into criticism from various parts of the House, although so far, much of the opposition has focussed on procedural issues.

Shadow Justice Minister Jack Straw has attacked the speed with which the Boundary Review will be conducted and its lack of transparency. Meanwhile, Graham Allen, Labour MP for Nottingham North and, as chair of the cross-party group on political and constitutional reform, someone who might be expected to support this bill, also expressed concern at the speed with which it was being "rushed through parliament".

The issue, of course, lies in the fact that the naïve principle that in a democracy, "the people decide" is very much determined by the detailed workings of the electoral system in use at the time. In the last election, the Conservative party scored 36 per cent of the vote (47 per cent of the seats) against Labour’s 29 per cent vote (39 per cent of seats) and Lib Dem 23 per cent of vote (9 per cent of seats).

The Lib Dems suffer greatly in the present system, which rewards parties whose support is concentrated regionally, and punishes those whose support is spread across the country. In addition, Labour benefit from holding some of the country’s smallest constituencies – something that a reduction in seat numbers and boundary review would almost certainly fix in a way that would not be to their advantage.

A purely proportional system (PR) – which some pundits claim to be the "fairest" option - would have given Conservatives 237 seats (as against 307 now), Labour 188 (as against 258) and Lib Dems 150 (57 now).

A system based on the Alternative Vote (AV), which allows votes to be transferred within constituencies until one candidate has an overall majority, is believed to favour the Lib Dems. In 2010, analysts believe that under AV, the Lib Dems would have overtaken Labour to become the second largest party in the Commons.

With all these factors in play, the chances of an open and non-partisan debate ensuing seem slight. Labour entered the last election in favour of AV – but may now vote against. The Lib Dems prefer PR, but will almost certainly take anything offered. The Conservatives like the status quo – but the Coalition would almost certainly not have survived their reneging on this pledge.

How the parties vote in the next 12 months, as well as how the country votes in the subsequent referendum may well decide the result of the next general election. ®